Tintin has been very lucky. He does not always feel lucky. But he knows he is.
He is lucky to have survived to the age of fourteen, even though he is so small. It helps that he is strong, from hours of mana-grinding exercise. He is in fact lucky to be so small. It means he will be able to carry more with him when he goes to the Scholomance, which he is lucky to be able to go to.
His parents sacrificed a great deal for his slot. In fact they sacrificed a great deal for him to be able to test for his slot - with no guarantee of attending. But he is clever, and he is strong, and he is fast. He knows French and Mandarin and Malay, and he can embarrass himself speaking in English and Tamil but he knows how to read them and pronounce isolated words which is the important thing, and his parents kept him far, far away from anyone who would expose him to Singlish. And he has Milou.
His parents did not jump for joy when divination revealed that his affinity was for firearms. Everyone knows that guns are not something you bring to the Scholomance. They go bad, and if they don't you run out of ammo, and if you spend your time in alchemy lab making ammo then you aren't spending it on something else. It's negative-sum. But you also don't ignore your affinity. The best result from that is a mediocre wizard. The most common result is a dead wizard.
So they bought him a gun. It was shiny, and it did not quite fit in his diminutive hands, so they had it altered. They taught him to shoot. They taught him to fight without a gun, in case he had to. They taught him to make powder and bullets, to oil and clean his weapon, to always carry a knife as well in case someone got too close.
They taught him to survive.
His backpack is almost as heavy as he is. He carries it without complaint. It has oil and bullets and clothes and mana crystals and reagents and the other things he will need. His hair is short, but not quite as short as another child's hair might be, and he is not dehydrated; after a certain point, the volume of his backpack was more of a problem than the weight, and adding another gram was not so efficient.
He will survive.
He will survive because he is prepared, and because he is lucky, and because those are the two things you need.